This invention relates to a method for manufacturing a sintered body mainly composed of .beta.'-sialon.
Heretofore, there have been proposed various methods for manufacturing sintered bodies having .beta.'-sialon as a main ingredient. For example, available is a method in which a .beta.'-sialon-based sintered body is manufactured by sintering a mixed compact formed of silica powder and aluminium powder in a nitrogenous nonoxidative gas atmosphere. According to such conventional method, however, the resultant sintered body is poor in compactness, exhibiting porosity of 40% or more. Moreover, its pore diameter is as large as 0.1 to 10.mu., so that it is poor in strength, resistance to oxidation, and chemical stability (especially stability in alkali), as well as in corrosion resistance as against high temperature molten aluminium. Further, the sintered body of the prior art is not suited for a practical use due to its high permeability.
Other conventional methods have also been subject to several shortcomings; cracks at sintering, uneven shrinkage to deteriorate dimensional accuracy, nonhomogeneous construction of sintered bodies which would nullify the outstanding properties peculiar to .beta.'-sialon.